Synthesis and Optical Properties of ZnO Nanoparticles in Submicron PS Hollow Reactors

ZnO nanoparticles were first encapsulated in submicron PS hollow microspheres through two-step swelling process of core-shell structured PMMA/PS (PMMA: polymethyl methao-rylate) microspheres in acid-alkali solution, and the ZnO precursors, i.e. the ethanol solu-tions of (CH₃COO)₂Zn and LiOH. The transmission electron microscope, X-ray diffraction, and thermogravimetric analysis results show that the feeding order of ethanol solutions of (CH₃COO)₂Zn and LiOH in the second swelling step has great influence on the loading efficiency and the size of ZnO nanoparticles, but little on their crystal form. The photolumi-nescence and UV-Vis absorption behavior of ZnO/PS microspheres show that the PS shell can effectively avoid the fluorescence quenching effect.